Monitoring System for Drilling Instruments

ABSTRACT

Drilling instruments may include a flexible portion, such as a flexible conduit and/or a universal joint. Sensors may be utilized to detect the position of various portions of the drilling instrument, such as the flexible conduit, the universal joint, and/or a drill bit assembly.

BACKGROUND

In some drilling applications, drilling may be implemented in a varietyof directions. For example, directional drilling and/or horizontaldrilling may be implemented in various formations, such as oil and gasformations, shale formations, coal bed formations, and/or tar sandformations. As another example, lateral holes or drainage holes may bedrilled to increase communication of a formation with a main boreholedrilled in a formation for production of various compounds.

SUMMARY

In various implementations, a drilling instrument may include a flexibleconduit, a universal joint, and/or sensor(s). The flexible conduit maybe disposed at least partially in the universal joint. The sensor(s) maydetect position information about the flexible conduit. A drillinginstrument may be monitored. A signal may be detected from sensor(s)disposed on a flexible conduit and position information of the flexibleconduit may be determined based at least partially on the detectedsignal. The performance of a drilling instrument may be tested. A firstcontrol signal(s) for a drill bit assembly of a drilling instrument maybe transmitted and a signal from sensor(s) may be detected. The controlsignal may be associated with a first position of the drill bitassembly. The position information of the drill bit may be determined atleast partially based on the detected signal, and the determinedposition information of the drill bit assembly may be compared to thefirst position of the drill bit assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the disclosure will hereafter be described withreference to the accompanying drawings, wherein like reference numeralsdenote like elements, and:

FIG. 1 illustrates a cross-sectional view of an implementation of aportion of an example drilling instrument.

FIG. 2 illustrates a cross-sectional view of an implementation of aportion of an example drilling instrument.

FIG. 3 illustrates a cross-sectional view of an implementation of anexample sensor arrangement.

FIG. 4 illustrates an implementation of an example sensor arrangement.

FIG. 5 illustrates an implementation of deflection in an exampleflexible conduit.

FIG. 6 illustrates an implementation of deflection in an exampleflexible conduit.

FIG. 7 illustrates an implementation of an example process formonitoring a drilling instrument.

FIG. 8 illustrates an implementation of an example processes for testingand/or monitoring a drilling instrument.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of various embodiments.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. In addition, the present disclosuremay repeat reference numerals and/or letters in the various examples.This repetition is for the purpose of simplicity and clarity and doesnot in itself dictate a relationship between the various embodimentsand/or configurations discussed. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact.

In some implementations, monitoring systems for drilling instruments ortools may be utilized when drilling into formations in the earth. Forexample, formations may include petroleum and/or gas reserves that maybe produced by drilling using drilling instrument(s) into the formation.The drilling may be multidirectional and thus, a drill instrumentcapable of drilling in various directions may be utilized. The drillinginstrument may include a universal joint, a flexible portion, sensors,and/or a drill bit assembly. For example, a drilling instrument mayinclude a flexible portion, such as a flexible conduit, that has theability to bend in the direction of the drill bit assembly. A universaljoint and/or the flexible conduit may bend in the direction of drillingand/or may transmit rotational power (e.g., via the transmission ofdrilling mud) to the drill bit to form the main borehole, lateralboreholes, drain holes, etc. The direction of drilling by the drill bitassembly may be based at least partially on the movement and/or positionof the universal joint and/or the flexible conduit.

As loads due to drilling operations and/or the formation are transmittedto the flexible conduit, universal joint, and/or bottom hole assembly,the orientation of the flexible conduit, universal joint, and/or bottomhole assembly (e.g., drill bit) may be distorted and/or altered from theexpected orientation based on control signals to the drillinginstrument. For example, the axial load path may pass through theuniversal joint (e.g., the flexible conduit may not be utilized totransmit torsional energy). In some implementations, the flexibleconduit may transmit the torsional energy and/or axial loads across thedrilling instrument. The universal joint and the flexible conduit maytransmit the torsional energy and/or axial loads across the drillinginstrument, in some implementations. By measuring the distortions and/oraltered orientations (e.g., from reference orientations and/or fromexpected orientations), a more accurate orientation of the flexibleconduit, universal joint, and/or bottom hole assembly may be determined.The determined orientation may be utilized in monitoring components ofthe drilling instrument, feedback loops, and/or in any other appropriatemanner.

FIG. 1 illustrates a cross-sectional view of an implementation of aportion 100 of an example drilling instrument. FIG. 2 illustrates across-sectional view of an implementation of a portion 200 of an exampledrilling instrument. The drilling instrument may include othercomponents not illustrated in FIGS. 1 and 2.

As illustrated in FIGS. 1 and 2, the drilling instrument may include afirst part 105 coupled to a second part 110. To allow multidirectionaldrilling (e.g., vertical, horizontal, and/or slant drilling), the secondpart 110 may move with respect to the first part 105.

A universal joint 115 may be disposed between the first part 105 and thesecond part 110. The universal joint 115 may allow movement (e.g.,bending, torsion about an axis, deflecting and/or axial compression ortension) of the second part 110 with respect to the first part 105. Theuniversal joint 115 may have one degree of freedom (e.g., a hinge), twodegrees of freedom (e.g., a Hooke's joint), and/or three degrees offreedom (e.g., a spherical ball joint). For example, a universal joint115 may bend in an x and/or y direction and/or the universal joint mayinclude a spherical joint that may move in an x, y, and/or z direction.The movement of the universal joint 115 may be measured radially aboutan axis and/or with respect to two or more axes (e.g., x, ycoordinates).

A flexible conduit 120 (e.g., a flexible tube) may be positioned atleast partially in the universal joint 115. For example, the flexibleconduit 120 may pass through the universal joint 115 and couple with adrill bit assembly 125.

In some implementations, one or more electrical wires may be disposed inor on the flexible conduit 120, and the one or more wires may pass fromone end to the opposing end of the flexible conduit 120 to enable thepassage of power and communication between systems disposed on eitherside of, or even attached to the flex tube.

The flexible conduit 120 may include at least a portion that isflexible. The flexible portion of the flexible conduit 120 may beelastically deformable and/or bendable. In some implementations, one ormore of the materials that form the flexible conduit 120 may be selectedfor properties of the materials. For example, at least a portion of theflexible conduit 120 may include materials that are conductive ornonconductive. At least a portion of the flexible conduit 120 mayinclude materials that are magnetic, nonmagnetic, and/or locallymagnetized, in some implementations. At least a portion of the flexibleconduit 120 may include embedded magnets. In some implementations, theflexible conduit 120 and/or portions thereof may include materials thatare opaque or transparent (e.g., to light, magnetic field and/orelectrical fields). For example, the flexible conduit 120 and/orportions thereof may include materials with properties to facilitatevisualization of sensors external to the conduit, imaging and/or sensingthe fluid flowing within the flexible conduit 120 and/or sensors. Insome implementations, the flexible conduit 120 may include markingsinside the flexible conduit to facilitate measuring the deflection ofthe flexible conduit.

The flexible conduit 120 may have one, two, and/or three degrees offreedom. For example, the flexible conduit 120 may bend in an x and/or ydirection (e.g., along an x-axis (not shown) and y-axis 132) and/or theflexible conduit 120 may deflect in an x, y, and/or z direction (e.g.,along an x-axis (not shown), y-axis 132, and z-axis 130, where thex-axis is perpendicular to the y-axis and the z-axis and/or torsionallyabout the z-axis). The movement of the flexible conduit 120 may bemeasured radially about an axis and/or with respect to two or more axes.For example, torsion of the flexible conduit 120 about the z-axis 130may occur. The flexible conduit 120 may bend about the x-axis and/ory-axis.

In some implementations, the movement of the flexible conduit 120 may berestricted. For example, at least a portion of a first surface 122 ofthe flexible conduit 120 may be coupled to at least a portion of a firstpart 117 of the universal joint 115 and/or at least a portion of asecond surface 123 of the flexible conduit 120 may be coupled to atleast a portion of a second part 118 of the universal joint 115. Themovement of the flexible conduit 120 may be restricted by this couplingarrangement, such that the flexible conduit 120 may be restricted fromrotating by the universal joint 115 and/or allowed to bend in twodirections (e.g., with respect to the first axis 130, the second axis132 perpendicular to the first axis, and a third axis (not shown)perpendicular to the first axis and the second axis).

In some implementations, the movement of the flexible conduit 120relative to the universal joint 115 may be based at least partially onthe type of coupling between the flexible conduit 120 and the universaljoint 115. For example, the flexible conduit 120 may conform to thelateral bending of the universal joint 115. The flexible conduit 120 maybe independently driven to rotate about the z-axis 130, for example, ifthe bit is driven with a motor (e.g., the motor is using the joint totransmit torque). In some implementations, the flexible conduit 120 orportions thereof may be free to rotate about the z-axis 130 (e.g., dueto the insertion of a rotary bearing that allows one end of the flexibleconduit 120 to rotate independently from the other end). For example,the flexible conduit 120 may be able to rotate about the z-axis 130without restriction when a universal joint, such as a 3D ball joint, isutilized and either end of the flexible conduit 120 may be attached tothe adjacent collar.

In some implementations, drilling mud may be channeled through thecenter of the flexible conduit and/or around the outside of the flexibleconduit. For example, the flexible conduit may transport drilling fluidacross the joint such that a pre-determined pressure is maintained.Thus, a seal for the universal joint, which may be structurally complexand/or the load/torsion transmitting member, against high pressures maynot be utilized when the drilling fluid is channeled through theflexible conduit.

In some implementations, drilling fluid may be transmitted across theuniversal joint external to the flexible conduit 120. The universaljoint may be sealed to inhibit damage and/or wear from the high pressuredrilling fluid. The fluid in the flexible conduit may be maintainedseparately from the drilling fluid external to the flexible conduit. Forexample, in a reverse circulating systems, where flow returns to thesurface via the flexible conduit, drilling fluid may be transmittedacross the universal joint external to the flexible conduit.

In some implementations, the sensors or portions thereof (e.g., thewires) may be protected (e.g., disposed in a protective housing) fromthe drilling mud. The direction of the drilling may be based at leastpartially on the movement of the universal joint 115.

The drill bit assembly 125 may be coupled to the second part 110 of thedrilling instrument and/or the flexible conduit 120. The drill bitassembly 125 may include a drill bit used in the cutting of theformation. In some implementations, as control of the position of thedrill bit is increased, the cutting tolerance may be improved. The drillbit assembly 125 may also include other components, such as a bit shaft;a collar; and/or receiving members to couple with the flexible conduit120, the second part 110 of the drilling instrument, and/or othercomponents of the drilling instrument.

The drill bit assembly 125 may include a rigid portion. In someimplementations, the drill bit assembly 125 may be more rigid (e.g.,less flexible) than the flexible conduit 120. Thus, knowledge ofposition information (e.g., relative and/or absolute, with respect toone or more axes) of the flexible conduit 120 may allow the positioninformation of the drill bit assembly 125 to be determined.

The drilling instrument may include one or more sensors 135 to monitorvarious components and/or properties of the drilling instrument. Asillustrated in FIGS. 1 and 2, the sensors 135 may be coupled (e.g.,directly and/or indirectly) to the flexible conduit 120 and/or theuniversal joint 115. The sensor(s) 135 may be disposed inside and/oroutside the flexible conduit, in some implementations. The sensor(s) maybe within the flexible conduit (e.g., at least partially integratedand/or embedded into the flexible conduit). In some implementations, thesensors 135 may be communicably coupled to the flexible conduit 120and/or the universal joint 115 such that properties of the flexibleconduit 120 and/or the universal joint 115 may be monitored.

The sensors 135 may include any appropriate sensing element, such asstrain gauges and/or displacement sensors. In some implementations,sensors 135 may include optical fibers. Sensors 135 may include eddycurrent displacement sensors, capacitive displacement sensors, magneticproximity sensors (e.g., Hall Effect sensors/magnetometers), linearvariable differential transformer sensors (LVDT sensors), differentialvariable reluctance transformer sensors (DVRT sensors), and/ornon-contact DVRT sensors, optical and ultrasonic ranging sensors. Thesensors 135 may detect temperature, pressure, position, linear and orangular deflection, compression, extension, axial loads, torque, and/orany other appropriate property of the drilling instrument and/orportions thereof.

The sensors 135 may measure changes in the shape of a component (e.g.,an optical fiber may be utilized to measure changes in the shape of theflexible conduit 120). In some implementations, sensors that includeeddy current displacement sensors may measure distances, displacements,and/or positions of electrically conductive components and/or portionsthereof. The eddy current displacement sensors may be communicablycoupled to various components of the drilling instrument and/or mayallow measurement without direct coupling to a component. The eddycurrent displacement sensors may inhibit wear on components of thedrilling instrument due to the sensor, during measurement. Capacitivedisplacement sensors may allow measurements in high linearity and/orwide ranges (e.g., from a few centimeters to a few nanometers).

The measurements by sensors 135 may be relative, differential and/orabsolute measurements, in some implementations. For example, thedeflection of the flexible conduit 120 may be measured with respect tothe first part 105 or a portion thereof, such as with respect to acollar 108 of the drilling instrument, as illustrated in FIG. 2.

Sensors 135 may measure one or more properties of a component of thedrilling instrument with which it is communicably coupled (e.g., adisplacement sensor may not make direct contact with a flexible conduitbut may allow measurement of deflection of and/or strain on a flexibleconduit). In some implementations, sensors 135 may measure more than oneproperty, and an arrangement of sensors and/or selection of types ofsensors may measure a first property while inhibiting measurement of asecond property and/or interference with the measurement of the firstproperty due to the second property. For example, a flexible conduit 120may expand due to temperature and/or forces on the drilling instrument.The measurement of the expansion due to temperature may be inhibitedwhile the measurement of the expansion due to forces on the drillinginstrument may be allowed. In some implementations, measurement ofproperties from pressure effects due to operation downhole may beinhibited.

The sensors 135 of the drilling instrument may be selected based on theproperty that is to be measured. The sensors 135 of the drillinginstrument may be selected based upon downhole conditions and/or theability of a sensor to resist damage due to exposure to downholeconditions. For example, sensors, such as eddy current sensors, mayresist damage from oil, dirt, dust, moisture, interference fields,and/or other downhole conditions.

The sensors 135 may transmit a signal that may be used, at least inpart, to determine position information (e.g., relative to apredetermined position and/or an absolute position) of at least aportion of the drilling instrument. For example, sensors may be coupled(e.g., communicably, directly and/or indirectly) to a flexible conduit120 to measure a property of the flexible conduit 120. The sensors 135may directly measure deflection and/or the sensors 135 may measure aproperty through which deflection may be determined. The sensors 135 maytransmit the signal from a measurement and the signal may be used todetermine position information of the flexible conduit 120.

Position information may include a relative and/or an absolute positionof a component. The position information may include deflection, degreeof bending, degree of torsion about an axis, degree of axial compressionand tension, and/or other information related to the position of acomponent. For example, the position information may include a deviationin position of a flexible conduit 120 from a predetermined position ofthe flexible conduit 120 (e.g., a reference position, an expectedposition associated with a control signal, and/or a previous position)and/or with respect to a component of the drilling instrument.

During operation, the position of the drill bit assembly 125 mayfluctuate since the flexible conduit 120 bends and/or moves torsionallyduring use due to the flexible properties of the flexible conduit 120.The position information of the flexible conduit 120 may be measured andat least partially utilized to determine a position of the drill bitassembly 125 and/or portions thereof. The direction of drilling may bedetermined based at least partially on a position of the drill bitassembly 125.

For example, utilizing measurements of the sensor(s) on the flexibleconduit and/or the universal joint, the pointing angle of the universaljoint may be determined. The position (e.g., direction) of the drill bitmay be determined from the determined pointing angle of the universaljoint. In some implementations, the sensor(s) on the flexible conduitand/or the universal joint may be utilized to determine the loads andtorsions being experienced by the universal joint and/or the flexibleconduit. The measurements from the sensor(s) on the flexible conduitand/or the universal joint may be utilized to determine the extent ofany angular rotation across the joint (e.g. in a 3D ball joint). Themeasurements from the sensor(s) on the flexible conduit and/or universaljoint may be utilized to determine differential pressure across theflexible conduit, temperature of the joint (e.g., for wear assessments),measurement of accumulated fatigue damage of the flexing members etc.

In some implementations, a rotation of a collar (e.g., collar 108 inFIG. 2) above a flexible conduit 120 and/or universal joint 115 may bedetermined. The rotation of the collar may be utilized with thedetermined position information of the flexible conduit 120, universaljoint 115, and/or drill bit assembly 125 to obtain real time (e.g.,during use) drill bit pointing direction. The drill bit pointingdirection may be utilized to improve control and/or steering (e.g., whencompared to a drilling instrument in which position information may notbe determined such that the drill bit pointing direction is assumed).

In some implementations, the measurements from sensors 135 may beutilized to determine the condition of a component of the drillinginstrument. For example, wear on a component and/or catastrophicmechanical failure may be inhibited by determining a condition of acomponent. In some implementations, the range of motion of a componentin good condition may be restricted to a predetermined range, anddetecting motion of the component outside of that range may identifywear on the component. Thus, the component may be replaced and/or fixed,for example, prior to excessive wear on the component and/or prior tocatastrophic mechanical failure of the drilling instrument.

In some implementations, the measurements from the sensors 135 may beutilized to determine the behavior and/or properties of components inthe bottom hole assembly. For example, one or more sensors may bedisposed anywhere along the bottom hole assembly, such as betweenconnections, for example. Information about the behavior of the bottomhole assembly may be determined based at least partially on measurementsfrom such sensors disposed along the bottom hole assembly and/or thesensors disposed proximate the flexible conduit. In someimplementations, the measurements from the sensors proximate one or morecomponents of the bottom hole assembly and/or the flexible conduit maybe utilized to determine performance issues, such as whether sticking inthe bottom hole assembly is located near the drill bit or near anothercomponent of the bottom hole assembly.

In some implementations, the rotating position proximate the drill bitmay be determined based at least partially on the information from oneor more additional sensors. For example, the additional sensors mayinclude a multi-axis accelerometer and/or a magnetometer. The rotatingposition of the bottom hole assembly may be determined at leastpartially based on information from the additional sensors and drill bitpointing information may be determined at least partially from thesensors 135 proximate the flexible conduit 120. The bottom hole assemblyrotating position and the drill bit pointing direction may be utilizedin a variety of operations of the drilling instrument. For example, howthe tool face is maintained and/or how resultant forces are applied maybe determined. A resultant force may include information about thedistribution angle and absolute force amount in the desired direction.During slip-stick scenarios, there may be a lag due to fast angularrotation and/or deceleration and a control system attempting to react toquickly changing conditions may not be able to reduce the slip-stickscenario, in some implementations. In some implementations, the controlsystem may utilize the information from the additional sensors and thesensors 135 near the flexible conduit 120 to apply a resultant forceover a time period. The absolute force in the desired direction may bereduced by the control system to result in less dog leg severity. Thus,in some implementations, slip-stick may be reduced since the controlsystem may be able to change over time rather than too quickly.

As illustrated in FIGS. 1 and 2, sensors 135 may be disposed proximateand/or coupled to the universal joint 115. The sensors 135 may generatesignals related to the position of the universal joint 115 and/or theflexible conduit 120. The position information about the universal joint115 may provide a degree of bending and/or torsion of the universaljoint 115 and/or information about the condition of the universal joint.For example, excessive bending and/or torsional movement (e.g., bendinggreater than a predetermined range) may be associated with excessivewear on the universal joint 115. In some implementations, sensors 135 onthe universal joint 115 may detect a seal breach causing oil to leak anddrilling fluid to seep in. For example, a sensor may short circuit ifdrilling fluid contacts the sensor. The short circuit may generate asignal that indicates the damage and thus the condition of a component(e.g., the portion proximate a leak). By monitoring the condition of theuniversal joint, the universal joint may be repaired and/or replacedprior to mechanical failure during use, for example.

In some implementations, a drilling instrument with sensors 135communicably coupled to a flexible conduit 120 and/or a universal joint115 may be simple and/or easy to maintain. Incorporating the sensors 135in, on, and/or proximate the universal joint 115 and/or flexible conduit120 may facilitate maintenance on components of the drilling instrument,cause less wear on parts, and/or simplify assembly of the drillinginstrument. Wires coupling sensors 135 on the flexible conduit 120 maybe coupled to the flexible conduit 120 and thus provide easy access tothe wires, avoiding the need to pass wires through the universal joint115.

In some implementations, the wires coupling sensors 135 on the flexibleconduit 120 may pass through the universal joint 115. Slip rings and/orinductive couplers may be utilized, in some implementations, to bypassthe joints.

In some implementations, sensor position in the drilling instrument maybe determined based on properties of the drilling instrument, such asdeflection properties of components (e.g., flexible conduit and/oruniversal joint) of the drilling instrument. For example, a sensorposition may be based on deflection properties of the flexible conduit.A flexible conduit may have restricted movement (e.g., due to couplingwith the universal joint). The sensors may be positioned proximate aportion and/or a surface of the flexible conduit that is more prone tomovement than another position. Sensor positions in the drillinginstrument may be determined based at least partially using finiteelement analysis. For example, finite element analysis may determinethat a first portion on a flexible conduit may be less sensitive todeflection (e.g., bending and/or torsion) than a second portion, andthus a sensor may be communicably coupled to (e.g., capable ofmeasuring) the second portion to detect deflection (e.g., bending and/ortorsion) of the flexible conduit.

In some implementations, a position of the flexible conduit may bedetermined based on properties of the drilling instrument, such asstrains in the structures that couple the flexible conduit and thecollar. For example, by measuring the strain in the structures that lockand/or otherwise couple the flexible conduit and the collar (e.g., aboveand/or below the joint) a deflection (e.g., bending and/or torsion) ofthe flexible conduit may be determined (e.g., since the flexible conduitmay act similar to a cantilevered beam imposing moments and loads on itsretention means).

FIG. 3 illustrates an implementation of an example arrangement 300 ofsensors. The sensors may include sensing elements, such as sets ofstrain gauges 305, 310, 315, 320, 325, 330, 335, 340 coupled to aflexible conduit 345. The strain gauges 305, 310, 315, 320, 325, 330,335, 340 may be used to measure the extent of strain on the flexibleconduit 345. The positional information may be determined from thesignals transmitted by the sensing elements 305, 310, 315, 320, 325,330, 335, 340. For example, the magnitude and/or the direction ofdeflection (e.g., bending and/or torsion) of the flexible conduit 345may be measured using the sensors.

As illustrated, the sets of sensing elements (e.g., two sensing elementsare shown per set, such as set 305, 315) are disposed at approximately90 degrees apart from each other circumferentially. In someimplementations, the sensors and/or sets of sensing elements may bedisposed between approximately 60 degrees and approximately 120 degreesapart from each other circumferentially. Positioning the sets of sensingelements (e.g., set 305, 315) at approximately 90 degrees apart fromanother set of sensing elements (e.g., 340, 330 and/or 335, 325) mayallow measurement of bending strains in two perpendicular planes.Although positioning the sets of sensing elements at 90 degrees apart isdescribed, the sets of sensing elements may be disposed about acomponent at various angles and positional information may be determinedbased on the signals from the sensing elements and/or the angles atwhich the sensing elements are disposed.

As illustrated, strain gauges 305, 315 are disposed about the flexibleconduit 345 at approximately 180 degrees apart circumferentially fromstrain gauges 310, 320. The positioning of the strain gauges may allowidentification of nonpositional influences, such as thermal stresses,compression loads, and/or tension loads, on the signal from the straingauges. Identification and/or reduction of the influence ofnonpositional influences may allow positional information to be moreaccurately determined using the signal(s) from the strain gauges.Pressure differentials (e.g., from operation downhole) may be identifiedin the signal due to the arrangement of the strain gauges and sopositional information may be more accurately determined.

In some implementations, the strain gauges may be coupled in aWheatstone bridge arrangement, as illustrated in the implementation ofan example sensor arrangement 400 in FIG. 4. The strain gauges 305, 310,315, 320 of a sensor arrangement 400 may be coupled in a Wheatstonebridge arrangement. The sensor arrangement 400 may reduce the effect ofnonpositional influences on the signal from the sensor. For example, thearrangement stays balanced (e.g., the effect of nonpositional influencesis inhibited) with thermal stresses, pressure stresses, compressionloads, and/or tension loads. Wheatstone bridge imbalances and/orimbalances in the arrangement may result in a voltage reading, eo, thatindicates bending strain. For example,

eo=Ks×εo×E

where Ks is the gauge factor, εo is the bending strain, and E is theapplied bridge voltage. Utilizing an arrangement, such as sensorarrangement 400, may allow a determination of positional informationwithin plus or minus ten degrees, in some implementations.

FIG. 5 illustrates an implementation of an example arrangement 500 ofsensors. The movement (e.g., deflection, bending and/or torsion) of theflexible conduit 120 from a first position 505 to a second position 510may be monitored by sensors 515, 520. The sensors 515, 520 may bedisplacement sensors. The displacement sensors 515, 520 may measureradial deflection of the flexible conduit 120. For example, thedisplacement sensors 515, 520 may measure the torsion of the flexibleconduit 120 about a first axis, which is normal to the second axis 530and the third axis 535. The displacement sensors 515, 520 may measurethe bending of the flexible conduit 120 in a direction along the secondaxis 530 and/or the third axes 535. The sensors 515, 520 may generate asignal related to the movement. The deflection 525 of the flexibleconduit 120 in a plane (e.g., the plane of the second axis 530 and thethird axis 535) may be determined from the generated signal. Thedetermined deflection 525 may then be utilized to determine the positionof the drill bit assembly 125. The movement may be in relation toanother position, such as in relation to a predetermined referenceposition, an initial determined position, and/or one or more componentsof the drilling instrument (e.g., a collar, a plane perpendicular to atleast a portion of drilling string, to the wellbore, and/or a firstportion of the drilling instrument).

FIG. 6 illustrates an implementation of an example movement of a portion600 of the drilling instrument. At least a portion of the flexibleconduit 120 may move during use from a first position 605 to a secondposition 610 and the deflection 615 may be determined. The movement maybe due to movement of the universal joint 115 and/or stress on theflexible conduit 120 (e.g., from downhole operation and/or from movementof the drill bit assembly 125). As illustrated in FIG. 6 and FIG. 5, insome implementations, the flexible conduit 120 may be capable ofdeflection in three directions along a first axis 620, a second axis530, and a third axis 535. The sensors may be disposed to be capable ofmeasuring the deflection in these three directions along axes 620, 530,535. The sensors may be capable of measuring the torsion of the flexibleconduit 120 about axes 620, 530, and/or 535 and/or the bending and/ortorsion of the flexible conduit along the axes 620, 530, and/or 535.

In some implementations, deflections during use may be based on controlsignals received by the drilling instrument to guide the drill bitassembly 125 to a predetermined position. The deflections may be due toother operational properties during use. For example, during use, theformation and/or drilling in the formation may act upon the drill bitassembly 125, universal joint 115, and/or flexible conduit 120 todeflect various components. As another example, the condition ofcomponents of the drilling instrument may allow deflections during useoutside a predetermined range, which may indicate a condition, such ascomponent wear.

FIG. 7 illustrates an implementation of an example process 700 formonitoring a drilling instrument. Signal(s) may be detected fromsensor(s) (operation 705). For example, sensors may measure positionalinformation and generate a signal related to positional informationand/or health/condition of a component of the drilling instrument. Thesensing elements of the sensor may detect a change (e.g., due toposition and/or strain on the component) and generate a signal based onthe change. The sensors may be coupled (e.g., communicably, directly,indirectly) to the flexible conduit and/or universal joint.

Position information for one or more components of the drillinginstrument may be determined at least partially based on the detectedsignal(s) (operation 710). For example, signals from sensors coupled tothe flexible conduit may be utilized to determine position information(e.g., deflection) of the flexible conduit. Signals from sensors coupledto the universal joint may be utilized to determine position informationof the universal joint. In some implementations, the signals fromsensors coupled to the flexible conduit and/or the universal joint maybe utilized to determine position information of the drill bit assembly.Knowledge of the drill bit assembly may improve control of the drillingdirection during use.

A determination may be made regarding whether the determined positioninformation is within a predetermined range (operation 715). Forexample, a predetermined range of movement may be allowed during use anddeterminations may be made regarding whether the movement is outside thepredetermined range of allowed movement. As another example, to accountfor fluctuations in sensor readings and/or inconsequential movements, apredetermined range of movement tolerance may be allowed. Adetermination may be made whether the flexible conduit, for example, isdeflecting based on a comparison of the determined position informationto the predetermined range of movement tolerance.

Property information may be determined based at least partially on thedetermined position information (operation 720). A property, such ahealth/condition of a component, may be determined based on the positioninformation. For example, when drilling mud in the drilling instrumentcontacts a sensor, which is ordinarily isolated from the drilling mud,the sensor may short-circuit. The signal from the sensor may thusindicate the oil leakage/drilling mud ingress and the health/conditionof the drilling instrument. As another example, as a component, such asthe flexible conduit, wears, the flexible conduit may allow a greaterelastic deformation than when the flexible conduit was initially put inuse. The sensors may detect the position of the flexible conduit, andthus the increase in movement of the flexible conduit, and thereby thehealth/condition of the flexible conduit may be determined. Monitoring ahealth/condition of various components of the drilling instrument mayallow early detection of problems and thus, inhibit mechanical failureduring use. For example, components may be repaired and/or replacedbased on the determined health/condition of the component.

A control signal may be determined based at least partially on thedetermined position information (operation 725). In someimplementations, sensors may be coupled to the flexible conduit. Thesensors may indicate position information for the flexible conduit andthe position of the drill bit assembly may be determined based on theflexible conduit position. The control signal may be determined based onthe determined position of the drill bit assembly. For example, thedetermined control signal may move the drill bit assembly (e.g., thedetermined control signal may be different from a previous controlsignal). As another example, the determined control signal may maintainthe drill bit assembly position (e.g., the determined control signal maybe the same or substantially similar to a previous control signal).

Process 700 may be implemented by various systems, such as systems 100,200, 300, 400, 500, and/or 600. In addition, various operations may beadded, deleted, or modified. For example, property information may notbe determined. As another example, a deflection may be determined basedon the signal(s). For example, a first position of a component may bedetermined from a first signal from a sensor and/or predetermined. Asecond position of a component may be determined based on a secondsignal. The deflection may be determined based on the difference betweenthe first position and the second position. In some implementations, thedetermined control signal may be generated to reconcile differencesbetween an expected position (e.g., based on a position associated witha previous control signal) of a drill bit assembly and the determinedposition of the drill bit assembly.

FIG. 8 illustrates an implementation of example processes 800 fortesting and/or monitoring a drilling instrument. A request for testingof a drilling instrument may be received (operation 805). The testingmay be downhole and/or prior to positioning the drill bit assemblydownhole. Testing may be performed to calibrate control signals toaccount for deviations between expected drill bit assembly positions(e.g., based on position associated with a first control signal) and adetermined drill bit position (e.g., based on position determined inresponse to receiving the first control signal). By calibrating thecontrol signals, the drill bit assembly drilling direction and/orposition may be more accurately controlled and/or control of a cuttingof a formation may be increased (e.g., when compared to not calibratingthe control signals). Testing the drilling instrument while downhole mayallow deviations from expected positions due to downhole influences tobe identified and control signals may be altered based on thedeviations.

First control signal(s) associated with a first position may betransmitted (operation 810). The control signal may include a speed, adirection and/or a position at which component(s) of the drillinginstrument should operate. For example, a first control signal may betransmitted to a drilling instrument and various components of thedrilling instrument may operate based on the control signal. Forexample, the universal joint and/or the flexible conduit may changeand/or maintain a position. The flexible conduit may transmit rotationalpower to the drill bit assembly. The first position may be associatedwith the first control signal based on previous testing of the drillinginstrument, factory presets, and/or expected position (e.g., based onmodels, calculations, and/or observations), for example.

Signal(s) may be detected from sensor(s) coupled to at least a portionof the drilling instrument (operation 815). For example, strain gaugesensing elements may be coupled to the flexible conduit in a Wheatstonebridge arrangement and detect deviations in position of the flexibleconduit. As another example, a displacement sensor communicably coupledto the flexible conduit may detect deviations in position along threeaxes. Sensors may be coupled to the universal joint. Sensors may beinhibited from directly measuring the drill bit assembly due toproperties of the drill bit assembly during use (e.g., drilling mudinterference and/or interference from cuttings).

Position information may be determined at least partially based on thedetected signal(s) (operation 820). For example, a position of aflexible conduit and/or drill bit assembly may be determined based atleast partially on signals from sensors coupled to the flexible conduit.The positional information may be deflections from a predeterminedreference point, in some implementations. The positional information maybe in relation to a portion of the drilling instrument or a planethrough the drilling instrument.

The determined position information may be compared to the firstposition associated with the control signal (operation 825). Forexample, the determined position information may be compared to thefirst position and the deviation from the expected position (e.g., thefirst position) may be determined. The deviations from the expectedposition may indicate a health/condition of a component (e.g., wear on acomponent may cause greater flexibility of a component). The deviationsfrom the first position may be based on formation properties (e.g.,greater resistance than expected) and/or downhole conditions (e.g.,pressure and/or temperature). The deviations from the expected position(e.g., first position) may allow the control signal to be altered toaccount for the deviations. For example, in some implementations,drilling instruments deviate from expected behavior during use downhole.Downhole operations may include unknowns, such as various resistancezones. Since the actual position of the drill bit assembly cannot bevisually determined by users when in use downhole, determining theposition of the drill bit assembly (e.g., through the sensors on theflexible conduit) may identify deviations in expected position. Once thedeviations are identified, control signals may be altered to account forthe deviations in operations downhole and greater control (e.g., whencompared with systems that do not compensate for deviations and/or whencompared with systems that assume a direction of a drill bit) of thecutting of a formation and/or greater cutting tolerances may beachieved, in some implementations.

In some implementations, the drilling instrument may be monitored(operation 830). For example, the components of the drilling instrumentsuch as the flexible conduit, universal joint, and/or drill bit assemblymay be monitored continuously and/or periodically.

During monitoring, the signal(s) from sensors may be detected (operation815) and position information may be determined at least partially basedon the detected signal(s) (operation 820). A comparison between thedetermined position information and an expected position (e.g., thefirst position, positions(s) and/or average position associated withprevious control signal(s), or other predetermined reference position)may be made. In some implementations, the monitoring may allow thecontrol signals to be altered in real time (e.g., during use downhole)to alter control signals to ensure a particular position duringoperations.

Process 800 may be implemented by various systems, such as systems 100,200, 300, 400, 500, and/or 600. In addition, various operations may beadded, deleted, or modified. In some implementations, various operationsof processes 700 and 800 may be combined and/or modified. For example,the request for testing may not be received. In some implementations,the drilling instrument and/or properties (e.g., positional informationand/or property information) thereof may not be monitored. Ahealth/condition of component(s) and/or property information may bedetermined based on the signals from the sensors.

In some implementations, the positional information may be utilized toincrease a cutting tolerance. For example, cutting tolerance and thusthe ability to make sharper cuts may be increased if deflection of theflexible conduit and/or drill bit assembly may be maintained within apredetermined range. The positional information may be utilized togenerate subsequent control signals to maintain the deflection of theflexible conduit within the predetermined range. For example, thepositional information of the flexible conduit and/or drill bit assemblymay be determined based at least partially on signals from sensorscoupled to the flexible conduit. The positional information may becompared to the predetermined range. If the positional information isoutside the predetermined range, then a control signal may be alteredsuch that deflection may be maintained within the predetermined range.

In some implementations, various systems and/or processes may allowvisualization of the behavior of the drill bit and/or drill bit assemblyin-situ. For example, a drilling instrument may include a sensor withtwo sets of Wheatstone bridge strain gauge sensing elements coupled to asurface of the flexible tube. The sensor may generate a signal thatallows a determination of the pointing direction (e.g., positionrelative to a collar above the flexible conduit) of the drill bit and/orthe amount of pointing displacement with respect to a tool face. Anabsolute deflection (e.g., bending and/or torsion about an axis) and/oramount of pointing may be determined at least partially based on signalsfrom the sensor, calibrations (e.g., calibrations based on testing ofthe drilling instrument and/or comparisons of the control signals,associated positions, and/or determined position information),temperature (e.g., measured by a sensor coupled to the drillinginstrument), and/or tool face information (e.g., properties of the toolface such as position and/or property information). In someimplementations, sticking and/or slipping of the drill bit may beidentified and the bending direction and effective pointing measurementmay be adjusted based on the sticking and/or slipping when determiningan absolute bending and/or amount of pointing of the drill bit.

In some implementations, determined position information and/or propertyinformation may be averaged and/or presented to a user (e.g., through acomputer interface).

In some implementations, since the performance of the drillinginstrument downhole may differ from the expected performance,determining the position information while downhole may enhanceperformance of the drilling instrument downhole. Determining propertyand/or position information in real time (e.g., concurrent withoperation of the drilling instrument) may facilitate steeringadjustments and/or rate of penetration controls. For example, thecontrol signals may be automatically adjusted based at least partiallyon determined position information and/or property information. Theautomatic adjustment may increase cutting tolerance and/or allow sharpercutting (e.g., when compared with drilling instruments in which controlsignals are not adjusted based on determined information from sensors.)

In some implementations, compression and/or torque may be measured forthe drilling instrument or portions thereof. Since the flexible conduitmay be disengaged from the compression and torque applied to theuniversal joint, a sensor (e.g., strain gauge) may be coupled to asurface of the universal joint. The sensor may measure compressionand/or torque on the universal joint. The compression and/or torque onthe universal joint may be related to the compression and/or torque onthe drill bit and/or drill bit assembly. Thus, compression and/or torqueon the drill bit and/or drill bit assembly (e.g., weight on bit and/ortorque on bit information) may be determined at least partially based onthe signals from the sensor on the universal joint.

Property information such as compression and torque on the drill bitassembly and/or universal joint based on the measurements by the sensoron the universal joint may provide real-time and/or in-situ performanceinformation. Performance information may indicate a quality and/orhealth/condition of a universal joint and/or bearings. For example, theuniversal joint may experience noise, such as knocking. Detection of theknocking, using the sensor on the universal joint, may facilitateidentification of premechanical failure events and/or inhibitcatastrophic failures during use through the identification. In someimplementations, a determination may be made whether performanceinformation deviates from expected values (e.g., based on modeling,simulation, and/or previous values) and/or predetermined values. Thedeviations in positional and/or property information from expectedvalues and/or predetermined values may indicate a health/condition ofthe universal joint and/or formation properties. The control signals maybe automatically adjusted based on deviations from expected valuesand/or predetermined values to obtain a drill bit position.

In some implementations, deflection and/or displacement of the universaljoint may be restricted. For example, strike ring(s) may restrictmaximum displacement. An angle sensor coupled (e.g., communicably,indirectly, and/or directly) to the universal joint may generate asignal and position information of the universal joint may be determinedbased on the signal. The absolute pointing displacement of the drill bitassembly may be determined based on the position information of theuniversal joint and the specified restricted displacement. In someimplementations, the health/condition of the drilling instrument may bedetermined based on the determined position information. For example,wear on the strike ring may increase the displacement range of theuniversal joint. The wear may be identified when a displacement greaterthan the predetermined maximum displacement is detected. In someimplementations, a loosening of the universal joint (e.g., from bendingthe bit box at the surface of the formation) may be identified when adisplacement greater than a predetermined maximum displacement isdetected by sensors coupled to the universal joint. Identifyingdecreasing health/condition of the universal joint (e.g., wear causingdeflections greater than a maximum deflection) may allow repair and/orreplacement of the universal joint prior to catastrophic mechanicalfailure during use and/or inhibit mechanical failure during use.

In some implementations, sensors may be coupled to various portions of abottom hole assembly (e.g., drill bit, drill collars, drill stabilizers,downhole motors, and/or rotary steerable system). For example, the flexor drill collar may facilitate bending of the bottom hole assembly. Thesensor may detect and/or monitor position information and/or propertiesof the bottom hole assembly so that a health/condition of the bottomhole assembly may be determined. The determined position information mayfacilitate achieving a dogleg. For example, the determined positioninformation may provide greater control of steering systems throughreal-time position information. In addition, sensors coupled to thebottom hole assembly may allow determination of mechanical load andforce information, which may allow determination of the health/conditionof various components (e.g., fatigue of flex collars and/or AmericanPetroleum Institute or “API” connections). Identification of thehealth/condition of various components of the bottom hole assembly mayallow preventative maintenance (e.g., repair and/or replacement ofcomponents in declining health/condition) and/or inhibit catastrophicmechanical failure during use.

In some implementations, sensors, such as strain gauges, may be disposedabout a circumference of a flexible conduit in an arrangement to inhibitsensitivity to deflection (e.g., bending and/or torsion about an axis).The sensors may detect inflation and/or deflation of the flexibleconduit due to differential pressure between the internal pressure ofthe flexible conduit and the annular pressure exerting an externalpressure on the flexible conduit. The signals from these sensors mayallow determination of properties such as downhole properties (e.g., bitplugging, bit nozzle washout, excessive pad pressure, and/orinsufficient pad pressure).

In some implementations, a sensor arrangement may be selected thatallows measurements of differential pressures on the flexible conduitwithout inhibiting the measurement of effects due to temperature and/orpressures (e.g., weight on bit, compression, and/or mono-axial stress).For example, if a flexible conduit is pre-stretched prior to positioningthe flexible conduit downhole, weight on bit may release an amount ofthe pre-stretching. A weight on bit and/or an indication of weight onbit may be determined based on the stretching of the flexible conduit(e.g., as measured by the sensor arrangement).

In some implementations, shallow hole testing may be performed. Forexample, sleeve motion may be visually checked during shallow holetesting. However, visual testing may be restricted (e.g., blocked,impaired, or otherwise difficult to visually ascertain) when attemptingto evaluate full displacement (e.g., in environments where steam isgenerated and/or at night). Sensors coupled to the sleeve and/oruniversal joint, for example, may measure displacement and allow testingto be performed when visual testing is restricted. Testing may includestrike ring placement (e.g., maximum displacements may be measured bysensors and compared to predetermined maximum displacements and/orexpected displacements). Strike ring placement may be difficult tovisually inspect (e.g., when strike rings are close in size such as 0.6,0.8 and 1 degree strike rings) and sensor measurements may facilitatetesting to ensure selection of the appropriate strike ring and/orplacement of the strike ring.

In some implementations, similar testing to the shallow hole testing maybe performed downhole. For example, since visual testing may bedifficult downhole, sensors may allow measurements for testing downhole.For example, displacement of a steering sleeve may be tested (e.g., asensor coupled to the steering sleeve may be utilized to measure thedisplacement of the steering sleeve and the measured displacement may becompared to predetermined ranges for displacements and/or expecteddisplacements in response to control signals). In some implementations,when the drilling instrument is off bottom, the universal joint may beeasily moved and testing of displacement ranges for various componentsof the drilling instrument may be performed (e.g., displacement may bemeasured, compared to predetermined ranges and/or expect ranges, and/ora performance of the component may be determined based on thecomparison).

In some implementations, the sensors may measure temperatures. Forexample, a sensor may be positioned proximate the universal joint suchthat the temperature change of the joint may be determined. A health(e.g., failure and/or degradation) of the universal joint may bedetermined based on the temperature changes, such as relatively largetemperature increases. Determinations of a health of the universal jointmay allow preventative action and/or maintenance (e.g., repair and/orreplacement) of the universal joint.

In some implementations, sensors coupled to the universal joint maydetermine a property of the universal joint. For example, mud invasioninto the universal joint may be determined by short circuit(s) in thesensors. Mud invasion may damage and cause various components in thedrilling instrument to fail. The short circuit will generate signalsthat indicate the abnormality. The early detection of mud in theuniversal joint, using the sensors, may reduce damage to components ofthe drilling instrument.

In some implementations, information from the sensors (e.g., positioninformation and/or properties) may be used in a closed loop feedback toprovide control of the direction in which a directional drillinginstrument propagates the hole (e.g., wellbore). The loop may be closeddownhole and/or include the surface of the formation.

In some implementations, position information may be graphicallyvisualized. The signals may be transmitted via conventional mud pulsetelemetry, wired drill pipes, and/or electromagnetic (EPulse)transmission. The signals may be utilized to generate a graphical userinterface that presents the information to a user. The positioninformation may be presented using auditory signals, in someimplementations. For example, a wired drill pipe may carry signals fromsensors to the surface of the formation and auditory signals may bepresented to users based on the signals.

In some implementations, various sensors may be utilized to determineproperties of the formation. For example, the sensor may be utilized todetermine the forces on the drill bit (e.g., based at least partially onpositional information and/or property information determined based atleast in part on signals from sensors on the flexible conduit and/oruniversal joint). The determined forces may be utilized to determineproperties of the formation, such as the type of rock and/or otherproperties. For example, a type of rock may be identified based at leastin part on the resistance to cutting by, and thus creating forces actingon, the drill bit. The properties of the formation may be utilized indetermining bit destruction characterizations and/or in commerciallyavailable simulation programs related to drilling in formations.

In some implementations, the sensors may be utilized in association withstuck bits. For example, when the bottom hole assembly gets stuckdownhole, it may be difficult to determine which component is the cause.The sensors may be utilized to identify if the drill bit is stuck basedat least partially on determined position information, determinedproperty information, and/or the health of the drill bit. If a stuckdrill bit is identified, a control signal (e.g., a control signal toapply more torque may be transmitted) may be transmitted based on theidentification and/or the drill bit sticking may be reduced.

In some implementations, although several universal joints have beendescribed, other types of universal joints may be utilized asappropriate. For example, the universal joint surrounding the flexibleconduit may be a larger flexible conduit (e.g., a flexible collar).Thus, rather than instrument the flexible collar, the bending of aninstrumented flexible conduit may be utilized (e.g., in conjunction withor in place of) in the various described systems and processes. Thesensors of the flexible conduit may measure the deflection of thecollar. The sensor(s) of the flexible conduit may include its ownsensors, power supply, and/or communication devices. For example,extension rods that pass through the flexible collar may be utilized toplace the communication sonde (e.g., Shorthop) closer to the PowerDrive.

In various implementations, a drilling instrument may include a flexibleconduit, a universal joint, and/or sensor(s). The flexible conduit maybe disposed at least partially in the universal joint. The sensor(s) maydetect position information about the flexible conduit.

Implementations may include one or more of the following features.Sensor(s) may be coupled to the flexible conduit. The positioninformation may include a measurement of the deviation in the positionof a flexible conduit from a predetermined position of the flexibleconduit. The position information may include a deflection of theflexible conduit. The drilling instrument may include a drill bitassembly and the flexible conduit may be coupled to at least a portionof the drill bit assembly. Sensor(s) may detect temperature, pressure,deflection, position, compression, extension, and/or torque. Theposition of a sensor may be based at least partially on deflectionproperties of the flexible conduit. A sensor may include sensingelement(s), such as strain gauge(s) and/or displacement sensor(s). Asensor may include two or more sensing elements, such as a first sensingelement set and a second sensing element set. The first sensing elementset and the second sensing element set may be radially disposed aboutthe flexible conduit. The first sensing element set may be disposedapproximately 60 degrees to approximately 120 degrees from the secondsensing element set. Sensor(s) may be coupled to the universal joint. Atleast one of the sensors may detect positional information about theuniversal joint.

In various implementations, a drilling instrument may be monitored. Asignal may be detected from sensor(s). The sensor(s) may be disposed ona flexible conduit, and the flexible conduit may be disposed at leastpartially in a universal joint of the drilling instrument. Positioninformation of the flexible conduit may be determined based at leastpartially on the detected signal.

Implementations may include one or more of the following features. Acontrol signal for the drilling instrument may be determined at leastpartially based on the determined position information. A determinationmay be made whether the determined position information is within apredetermined range. A control signal may be determined based at leastpartially on whether the detected signal is within the predeterminedrange. Property information may be determined based at least partiallyon the determined positional information. The property information mayinclude temperature, pressure exerted on the universal joint,compressive force exerted on the universal joint, and/or healthinformation about the drilling instrument.

In various implementations, the performance of a drilling instrument maybe tested. First control signal(s) for a drill bit assembly of adrilling instrument may be transmitted. The control signal may beassociated with a first position of the drill bit assembly. A signalfrom sensor(s) may be detected. The sensor(s) may be disposed on aflexible conduit of the drilling instrument. The flexible conduit may becoupled to the drill bit assembly. The position information of the drillbit may be determined at least partially based on the detected signal.The determined position information of the drill bit assembly may becompared to the first position of the drill bit assembly.

Implementations may include one or more of the following features.Second control signal(s) may be transmitted at least partially based onthe comparison of the determined position information of the drill bitassembly to the first position of the drill bit assembly. The secondcontrol signal(s) may be substantially similar to the first controlsignal(s) and/or substantially different from the first controlsignal(s). Position information of a universal joint may be determinedat least partially based on signals transmitted from additionalsensor(s) coupled to the universal joint. The flexible conduit may bedisposed at least partially in the universal joint of a drillinginstrument. The drilling instrument may be monitored based at leastpartially on the comparison of the determined position information ofthe drill bit assembly to the first position of the drill bit assembly.

Although strain gauges and/or displacement sensors have been describedas sensing elements in sensor(s), any appropriate sensing elementsand/or combinations thereof may be utilized in various implementations.Although sensors have been described as including sensing element(s),the sensors may include sets of sensing elements. A set of sensingelements may include one or more sensing elements.

In various implementations, coupling has been described. Coupling mayinclude direct and/or indirect coupling. For example, coupling mayinclude gluing, bonding, affixing, and/or otherwise adhering. Couplingmay include disposing at least a portion of an object in a receivingmember of another object. For example, a portion of the drill bitassembly may include a receiving member for the flexible conduit. Theflexible conduit and the drill bit assembly may be coupled through thereceiving member. Communicably coupling may include coupling such that afirst object is in communication with another object, for example. Asensor that is communicably coupled to a flexible conduit may or may notbe directly coupled to the flexible conduit and may measure the flexibleconduit deflection and/or other properties.

Although users have been described as a human, a user may be a person, agroup of people, a person or persons interacting with one or morecomputers, and/or a computer system. Various implementations of thesystems and techniques described here can be realized in digitalelectronic circuitry, integrated circuitry, specially designed ASICs(application specific integrated circuits), computer hardware, firmware,software, and/or combinations thereof. These various implementations caninclude implementation in one or more computer programs that areexecutable and/or interpretable on a programmable system including atleast one programmable processor, which may be special or generalpurpose, coupled to receive data and instructions from, and to transmitdata and instructions to, a storage system, at least one input device,and at least one output device.

These computer programs (also known as programs, software, softwareapplications or code) include machine instructions for a programmableprocessor, and can be implemented in a high-level procedural and/orobject-oriented programming language, and/or in assembly/machinelanguage. As used herein, the term “machine-readable medium” refers toany computer program product, apparatus and/or device (e.g., magneticdiscs, optical disks, memory, Programmable Logic Devices (PLDs)) used toprovide machine instructions and/or data to a programmable processor,including a machine-readable medium that receives machine instructionsas a machine-readable signal. The term “machine-readable signal” refersto any signal used to provide machine instructions and/or data to aprogrammable processor.

To provide for interaction with a user, the systems and techniquesdescribed here can be implemented on a computer (e.g., laptop, tablet,smartphone) that may include a display device (e.g., a LCD (liquidcrystal display) monitor) for displaying information to the user, akeyboard, and/or a pointing device (e.g., a mouse) by which the user canprovide input to the computer. Other kinds of devices can be used toprovide for interaction with a user as well; for example, feedbackprovided to the user by an output device can be any form of sensoryfeedback (e.g., visual feedback, auditory feedback, or tactilefeedback); and input from the user can be received in any form,including acoustic, speech, or tactile input (e.g., touch screens).

It is to be understood the implementations are not limited to particularsystems or processes described which may, of course, vary. It is also tobe understood that the terminology used herein is for the purpose ofdescribing particular implementations only, and is not intended to belimiting. As used in this specification, the singular forms “a”, “an”and “the” include plural referents unless the content clearly indicatesotherwise. Thus, for example, reference to “a sensing element” includesa combination of two or more sensing elements and reference to “asensor” includes different types and/or combinations of sensors.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions andalterations herein without departing from the spirit and scope of thepresent disclosure.

Although the preceding description has been described herein withreference to particular means, materials and embodiments, it is notintended to be limited to the particulars disclosed herein; rather, itextends to all functionally equivalent structures, methods and uses,such as are within the scope of the appended claims

What is claimed is:
 1. A drilling instrument comprising: a universaljoint; a flexible conduit disposed at least partially in the universaljoint; and one or more sensors to detect position information of theflexible conduit.
 2. The drilling instrument of claim 1 wherein one ormore of the sensors is coupled to the flexible conduit.
 3. The drillinginstrument of claim 1 wherein the position information comprises atleast one of a measure of a deviation in position of the flexibleconduit from a predetermined position of the flexible conduit or adeflection of the flexible conduit.
 4. The drilling instrument of claim1 further comprising a drill bit assembly, wherein the flexible conduitis coupled to at least a portion of the drill bit assembly.
 5. Thedrilling instrument of claim 1 wherein at least one of the sensorsmeasures at least one of temperature, pressure, deflection, position,compression, extension, or torque.
 6. The drilling instrument of claim 1wherein a position of at least one of the sensors is based at leastpartially on deflection properties of the flexible conduit.
 7. Thedrilling instrument of claim 1 wherein at least one of the sensorscomprises at least one sensing element, and wherein at least one of thesensing elements comprises at least one of a strain gauge or adisplacement sensor.
 8. The drilling instrument of claim 1 wherein atleast one of the sensors comprises a first sensing element set and asecond sensing element set radially disposed about the flexible conduit,and wherein the first sensing element set is disposed approximately 60degrees to approximately 120 degrees apart circumferentially from thesecond sensing element set.
 9. The drilling instrument of claim 1wherein at least one of the sensors is coupled to the universal joint.10. The drilling instrument of claim 1 wherein at least one of thesensors detects positional information of the universal joint.
 11. Amethod of monitoring a drilling instrument comprising: detecting asignal from one or more sensors, wherein at least one of the sensors isdisposed on a flexible conduit positioned at least partially in auniversal joint of a drilling instrument; and determining positioninformation of the flexible conduit based at least partially on thedetected signal.
 12. The method of claim 11 further comprisingdetermining a control signal for the drilling instrument based at leastpartially on the determined position information.
 13. The method ofclaim 12 further comprising determining whether the determined positioninformation is within a predetermined range, and wherein the controlsignal is determined based at least partially on whether the detectedsignal is within the predetermined range.
 14. The method of claim 11further comprising determining property information based at leastpartially on the determined positional information.
 15. The method ofclaim 14 wherein the property information includes at least one oftemperature, pressure exerted on the universal joint, compressive forceexerted on the universal joint, or condition of the drilling instrument.16. A method for testing the performance of a drilling instrumentcomprising: transmitting at least one first control signal for a drillbit assembly of the drilling instrument, wherein the at least one firstcontrol signal is associated with a first position of the drill bitassembly; detecting a signal from one or more sensors, wherein at leastone of the sensors is disposed on a flexible conduit coupled to thedrill bit assembly; determining position information of the drill bitassembly based at least partially on the detected signal; and comparingthe determined position information of the drill bit assembly to thefirst position of the drill bit assembly.
 17. The method of claim 16further comprising transmitting at least one second control signal basedat least partially on comparing the determined position information ofthe drill bit assembly to the first position of the drill bit assembly.18. The method of claim 17 wherein at least one of the second controlsignals is either substantially similar to at least one of the firstcontrol signals or substantially different from at least one of thefirst control signals.
 19. The method of claim 16 further comprisingdetermining position information of a universal joint of the drillinginstrument at least partially based on signals transmitted from one ormore additional sensors, wherein the one or more additional sensors arecoupled to the universal joint, and wherein the flexible conduit isdisposed at least partially in the universal joint.
 20. The method ofclaim 16 further comprising monitoring the drilling instrument based atleast partially on comparing the determined position information of thedrill bit assembly to the first position of the drill bit assembly.